ANDROID: block: Support submitting passthrough requests with small segments
If the segment size is smaller than the page size there may be multiple segments per bvec even if a bvec only contains a single page. Hence this patch. Bug: 308663717 Bug: 319125789 Change-Id: I81516bf6da8ce3e4e60651ab2bd379080e7d3482 Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Juan Yescas <jyescas@google.com>
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@ -531,7 +531,7 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio)
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unsigned int nr_segs = 0;
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bio_for_each_bvec(bv, bio, iter)
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nr_segs++;
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nr_segs += blk_segments(&rq->q->limits, bv.bv_len);
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if (!rq->bio) {
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blk_rq_bio_prep(rq, bio, nr_segs);
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18
block/blk.h
18
block/blk.h
@ -91,6 +91,24 @@ struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
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gfp_t gfp_mask);
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void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs);
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/* Number of DMA segments required to transfer @bytes data. */
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static inline unsigned int blk_segments(const struct queue_limits *limits,
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unsigned int bytes)
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{
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if (!blk_queue_sub_page_limits(limits))
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return 1;
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{
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const unsigned int mss = limits->max_segment_size;
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if (bytes <= mss)
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return 1;
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if (is_power_of_2(mss))
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return round_up(bytes, mss) >> ilog2(mss);
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return (bytes + mss - 1) / mss;
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}
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}
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static inline bool biovec_phys_mergeable(struct request_queue *q,
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struct bio_vec *vec1, struct bio_vec *vec2)
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{
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